Method and apparatus for packaging agricultural plant material

ABSTRACT

A bale of cut silage 2 is fed into a sheath 8 of flexible packaging. Apparatus 1 comprises thermal sealing/cutting heads 14,15 and intermediate blades 20. Heads 14,15 seal a rear end 21 of package 22; blades 20 separate package 22 from the remainder of sheath 8; heads 14,15 provide a further sealed end 9 for sheath 8 ready to receive the next bale 2 to be packaged.

The present invention relates to a method and apparatus suitable forpackaging agricultural plaint material, and in particular to such amethod and apparatus for packaging animal fodder such as silage or thelike.

Typically, agricultural plant material, such as silage, is packaged forstorage, in bale form, by wrapping a plastics sheet around the bale andsecuring in place. Usually, the plastics sheet is precut to apredetermined size and shape dependent on the size and shape of thebales to be packaged. Using known techniques it is difficult to producea silage bale wrapper machine which may be used for wrapping bothcylindrical and rectanglar (or square) bales. Furthermore, the procedurefor wrapping individual bales is both complicated and time consuming.

I have now devised an improved method and apparatus for packagingagricultural plant material which alleviates some of the aforementioneddifficulties.

According to a first aspect of the invention, there is provided a methodof packaging agricultural plant material, which method comprises feedinga quantity of said agricultural plant material into a sheath of flexiblepackaging material susceptible to thermal bonding (such as a plasticssheet material) and subsequently:

a) thermally sealing a first portion of the sheath to form a discretepackage for the abovementioned quantity of plant material;

b) separating the portion of the sheath comprising the discrete packagefrom the remainder of the sheath: and

c) thermally sealing a second portion of the sheath to provide aneffectively closed end for the remainder of the sheath.

It is preferred that the end of the sheath into which the plant materialis initially fed is effectively closed prior to introduction of theplant material into the sheath.

Typically, the plant material is fed into the sheath in discretequantities, such as bales, although it is envisaged that the plantmaterial may, in certain circumstances be continuously fed into thesheath.

Advantageously, the feeding of the plant material into said sheathcauses a length of the sheath to be pulled (or wrapped) over the plantmaterial.

Typically, the sheath will be generally tubular, and it is preferredthat a predetermined length of the sheet material is pulled over thequantity of plant material prior to steps a,b and c referred to abovebeing effected. The tubular sheath may be of circular section, althoughin some embodiments, the tubular sheath may be of square or rectangularsection or the like.

The use of thermal sealing, is particularly advantageous in allowing, atleast two, and preferably all three, of steps a,b and c referred toabove, to be carried out in a single operation. Thermal sealing isbeneficial in optimising the efficiency of the process, and apparatus ashereinafter described, both in terms of speed and the reliability of theresulting seals.

Advantageously, the operation of steps a,b and c referred to above iscontrolled by control means actuable when a selected length of thesheath has been pulled over the quantity of plant material; such controlmeans may include one or more stop member arranged to ensure initiationof one or more of the thermal sealing steps.

Advantageously, the sheath material will be dispensed from a store ofsheath material under the action of force exerted on the effectivelyclosed end of the sheath by the quantity of plant material being fedinto the sheath.

According to a second aspect of the invention, there is providedapparatus for packaging agricultural plant material, which apparatuscomprises:

a) a dispenser of elongate flexible material susceptible to thermalbonding, which flexible material is arranged to define a sheath intowhich the plant material can be fed;

b) first thermal sealing means arranged to seal first portions of thesheath together at a first position;

c) second thermal sealing means arranged to seal second portions of thesheath together at a second position spaced from the first position; and

d) separating means arranged to separate adjacent portions of the sheathat a position intermediate between the first and second positions.

Advantageously the dispenser includes housing means arranged to containa dispensable length of the sheath material, which housing furtherdefines an aperture through which agricultural plant material can befed.

Typically, the sheath will be generally tubular, and stored inconcertina or roll form in the housing.

It is preferred that the housing is provided with a continuous slit orslot through which said flexible sheath can be dispensed.

The housing is preferably annular in configuration thereby defining asubstantially circular aperture therethrough.

Advantageously, the sheath is provided with an effectively closed endsuch that the sheath acts as a pouch into which the plant material maybe fed.

It is preferred that the first and second scaling means and theseparating means act on the sheath at a position to the rear of aquantity of plant material being packaged. Advantageously, the firstscaling means is arranged to provide an effectively sealed (or closed)termination (or end) to a preceding package of plant material, with thesecond scaling means arranged to produce an effectively sealed (orclosed) termination (or end) to a following package. The separatingmeans separates the preceding package from the following package.

Advantageously, the first and second sealing means, and also preferablythe separating means, are actuable in a single operation therebyeffecting sealing and separation in a single operation.

It is preferred that feeding means is provided arranged to feed theplant material into the sheath. Typically, the feeding means comprises aconveyor or the like, which is typically spiked.

Advantageously, the sheath dispenser will be mounted on support means,which typically comprises a support platform advantageously inclined atan angle to the horizontal such that the plant material passes into thesheath under the influence of gravity. Alternatively, the plant materialmay be forced through mechanically (for example, by means of ahydraulically operated mechanism or the like). Typically the supportplatform will be provided with support rollers, conveyors or the likeover which the packaged plant material may pass.

Advantageously, the separating means comprises at least one bladeelement, heated wire or the like.

In a preferred embodiment of the invention, the first and second scalingmeans comprise respective pairs of sealing elements which may be urgedtoward one another to effect scaling.

Advantageously at respective member of each pair of scaling elements isprovided on a respective one of a pair of movable heads. Advantageously,at least one of the pair of movable heads is further provided with ablade element, heated wire or the like, typically positioned between thescaling elements.

It is preferred that the movable heads are movable under the influenceof pneumatic or hydraulic cylinder/ram arrangements.

Typically, control means are provided to automatically control theoperation of the movable heads. Advantageously, the control meanscomprise one or more position detectors arranged to be actuated when aselected length of the sheath has been dispensed.

The invention will now be further described in a specific embodiment byway of example only, and with reference to the accompanying drawings, inwhich:

FIG. 1 is a schematic representation of apparatus according to thesecond aspect of the invention for use in the method according to thefirst aspect of the invention;

FIG. 2 is an explanatory perspective view of a part of the apparatus ofFIG. 3 is a cross section along line A--A of FIG. 2; and

FIG. 4 is a schematic view of an automatic control system suitable foruse with the apparatus of FIGS. 1 to 3.

Referring to the drawings, and initially to FIG. 1 in particular, thereis shown apparatus 1 shown for use in packaging harvested agriculturalmaterial (typically bales of cut silage 2).

The apparatus illustrated comprises an inclined conveyor 3 provided withspikes 4 onto which bales of cut silage are loaded. The conveyor 3transports the bales 2 upwardly to the open mouth of a packagingcartridge 5 which is retained on an inclined support platform 6 by meansof a retaining bracket 7. Alternative types of conveyors or liftingdevices which may be used include hydraulic arms or the like.

Referring to FIGS. 2 and 3, the packaging cartridge 5 comprises anannular housing containing a tubular sheath 8 of flexible sheet material(typically plastics sheet) which is closed (e.g. as illustrated along aseal line 9 by bonding).

The seat as shown is linear, although is it, of course, possible toprovide a seal which is a closer approximation to a point seal.

The sheath 8 is stored in a rolled or concertina form in the housing andmay be dispensed therefrom through, an annular slit 10 in the housing inthe downstream direction of processing of the bale 2.

On reaching the top of the spiked conveyor 3, the bale 2 passes underthe influence of gravity through the annular cartridge 5 and overrollers 11 (or other suitable feed system, such as a conveyor or thelike) on inclined support platform 6 until is downward motion is checkedby abutting stop 12. As the bale rolls over rollers 11 toward stop 12,the tubular sheath 8 is pulled out of cartridge 5 to provide asubstantially complete covering for the bale 2.

When the bale 2 contacts stop 12, a limit switch 13 is actuated. Limitswitch 13 forms part of an automatic control system for the apparatuswhich will be described in greater detail below. Actuation of switch 13causes A pair of scaling/cutting heads 14/15 to be urged toward oneanother to the rear of bale 2, by means of hydraulic or pneumaticcylinder/ram arrangements 16/17. Movement of the sealing/cutting heads14/15 toward one another causes a portion of sheath 9 to be wrappedaround the rear of bale 2.

Each sealing/cutting head 14/15 comprises a pair of heating elements18,19 arranged one either side of an intermediate blade element 20. Asscaling/cutting heads 14/15 engage one another (with a double thicknessof sheath 8 sandwiched therebetween), corresponding heating element 18and 19 abut one another and are energised thereby causingcorrespondingly "sandwiched" portions of sheath 5 to be thermally bonded(sealed) together. At the same time, the action of corresponding bladeelements 20 causes the portion of the sheath 8 intermediate the"sandwiched" portions to be served. In this way, the action of thesealing/cutting heads causes the package for the bale 2 to be completedand provided with a rear sealed end 21; separates the sealed package 22from the reminder of the sheath 8; and provides a further sealed end 9for the sheath ready to receive the next bale 2 to be packaged. Theblade may, in some embodiments, be retractable; in other embodiments thecutting/scaling blade may both and seal in a single operation.

Subsequent to sealing and cutting, the heads 14,15 are retracted totheir starting position, and stop 12 retracted by means of hydraulic orpneumatic cylinder/ram 23 enabling scaled package 22 to proceed undergravity over rollers 11 and be removed from the apparatus fortransportation to a storage location.

Packaging cartridge 5 is demountable from the apparatus (specially frommounting bracket 7) and may be replaced when the stored supply of sheath8 is exhausted.

Referring to FIG. 4, there is shown schematically the control system foroperating the apparatus. Hydraulic rain 24 provides pressurised fluid tocylinders 16,23 via relevant ports of respective solenoid control valves25,26,27. A programmable logic controller 28 (or other logic (device)controls the switching of valves 25,26,27 and is responsive to signalinput from the limit switch 13 provided on stop ram 23. Alternatively,instead of the hydraulic system described and illustrated, acorrespondingly operating pneumatic system may be employed.

I claim:
 1. Apparatus for packaging agricultural bales, comprising:(a)an annular housing mounted on a support platform comprising supportrollers and conveyors for dispensing elongate flexible material defininga sheath into which said bale is able to be fed, said annular housingbeing inclined at an angle to the horizontal so that said bale passesinto said sheath under gravity; (b) first thermal sealing means beingarranged for sealing first portions of said sheath together at a firstposition; (c) second thermal sealing means being arranged for sealingsecond portions of said sheath together at a second position spaced fromsaid first position, wherein said first thermal sealing means and saidsecond thermal sealing means comprise respective pairs of sealingelements which are able to be urged toward one another for effectingsealing; and, (d) separating means being arranged for separatingadjacent portions of said sheath at a position intermediate said firstpositions and said second positions.
 2. The apparatus according to claim1, wherein said housing has a continuous slit or slot through which saidflexible sheath is dispensable.
 3. The apparatus according to claim 1,wherein said housing defines an aperture through which said bale can beintroduced.
 4. The apparatus according to claim 1, wherein said firstthermal sealing means, said second thermal sealing means and saidseparating means are arranged for acting on the sheath at a position tothe rear of said bale being packaged.
 5. The apparatus according toclaim 1, wherein said first thermal sealing means is arranged forproviding an effectively sealed termination to a preceding bale, withsaid second thermal sealing means being arranged for producing aneffectively sealed termination to a subsequent bale.
 6. The apparatusaccording to claim 5, wherein said first thermal sealing means, saidsecond thermal sealing means and said separation means are actuable in asingle operation thereby effecting sealing and separation in a singleoperation.
 7. The apparatus according to claim 6, further comprisingfeeding means being arranged for introducing said bale into said sheath.8. The apparatus according to claim 7, wherein said feeding meansincludes a conveyor.
 9. The apparatus according to claim 1, wherein saidseparating means comprises at least one blade element.
 10. The apparatusaccording to claim 1, wherein said separating means comprises at leastone heated wire.
 11. The apparatus according to claim 1, wherein arespective number of each pair of sealing elements has thereon arespective one of a pair of movable heads.
 12. The apparatus accordingto claim 11, wherein at least one of the pair of movable heads has ablade element positioned between said sealing elements.
 13. Theapparatus according to claim 11, wherein at least one of the pair ofmovable heads has a heated wire positioned between said sealingelements.
 14. The apparatus according to claim 11, further comprisingcontrol means for automatically controlling the operation of saidmovable heads.
 15. The apparatus according to claim 14, wherein saidcontrol means comprises at least one position detector being arrangedfor being actuated when a selected length of said sheath has beendispensed.